How do i retrieve a deleted note on my iphone 6

Is your iPhone running iOS 9?

If it is you can easily recover a deleted note by clicking going to recently deleted in notes and clicking edit, and checking the notes you want to move.

NOTE: if you don't see this click the back arrow at the top left of your screen.

Do you have a Mac running OS X El Capitan... If not you may want to update your iPhone or Mac to recover the note in the recently deleted section of notes (which is a new feature in these OSs). If you really don't want to update either or don't have a Mac you can go on iCloud.com with your PC and see if your note is still there or in the recently deleted section there.